<?php 
session_start();
$upd = $_GET['upd'];
$id = $_GET['id'];
$order=$_SESSION['cart'];
foreach($order as $key=>$value){
	if($value['id']==$id){
		switch($upd){
			case 0:
			if($value['num']>1){
				$order[$key]['num']-=1;
			}else{
				unset($order[$key]);
			}
			break;
			case 1:
			$order[$key]['num']+=1;
			break;
			default;
		}
		header("location:cart.php");
	}
	if($upd==""){
		$sum +=$value['price']*$value['num'];
		header("location:order.php");
	}
}
$_SESSION['num']=array_sum(array_column($order,"num"));
$_SESSION['sum']=$sum;
$_SESSION['cart']=$order
?>